Technical Field
The present disclosure relates to the field of semiconductor manufacturing, and more particularly to a method and system for dispatching materials (e.g., wafer lots) through process chambers in machines located inside a semiconductor manufacturing plant.
Description of the Related Art
At present, in a semiconductor manufacturing plant (fab), the number of equipment having process chambers typically constitutes about 40% of the total equipment in the entire fab. However, an existing real-time dispatcher (RTD) system in the fab usually only dispatches lots at the machine level, and do not take into account the different process chambers within the equipment.
For example, equipment that has process chambers often include at least two chambers (per machine) performing the same or different process. The process chambers in each machine may be operated in different modes, for example serial or parallel. Parallel mode means that different wafers from a same batch of wafers can simultaneously enter different chambers for processing. Serial mode means that the wafers are processed sequentially in the different chambers, from one chamber to the next.
In existing fabs, although an RTD system has been installed on most machines having process chambers, the RTD system can usually only support the host station operator in dispatching materials. In particular, the RTD system often lack the capability to accurately determine the loading conditions at the different process chambers based on the quantity of wafer lots awaiting processing at each machine. Since the RTD system cannot determine whether there is wafer pile-up at each machine, the task of allocating the workflow is often performed manually by an experienced engineer or technician, who would specify which wafer lot(s) goes to which process chamber. However, the current method of manually allocating the workflow is inefficient for high volume manufacturing. As a result, an existing RTD system is unable to maximize/optimize manufacturing throughput.